Bump uglify-js from 2.2.5 to 3.9.1
Bump uglify-js from 2.2.5 to 3.9.1

Bumps [uglify-js](https://github.com/mishoo/UglifyJS2) from 2.2.5 to 3.9.1.
- [Release notes](https://github.com/mishoo/UglifyJS2/releases)
- [Commits](https://github.com/mishoo/UglifyJS2/compare/v2.2.5...v3.9.1)

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@github.com>
BoilerplateMVC/Marionette-Require-Boilerplate,BoilerplateMVC/Marionette-Require-Boilerplate